Benadryl is ok, but it has lots of possible side effects. It always made me really drowsy into the next day.
Melatonin is better, it acts as a strong anti-oxidant to protect from MDMA neurotoxicity, and is also good for your immune system. Sometimes it can take almost 2 hours to kick in though...even then, sometimes it's not powerful enough.
I would highly recommend Kava kava. It's very potent if you get the right kind. It's very similar to weed in the regard that it adds a positive cozy cushion to pretty much any drug you add it to. It's also known to stop RLS (my gf can attest to this) and it also relaxes your muscles & suppresses appetite. It works somewhat on the GABA receptos as well as some other parts of your brain.
Try it....you'll probably be surprised it's legal.